This topic

Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

POTS — Tue, 06 Jan 2026 17:36:25 GMT

The Smart Hub 2 plugs into a BT Master Socket. Let's say that analogue telephone equipment had been plugged into the BT Master Socket. Would that equipment now function if plugged into the Smart Hub 2 Telephone Port?

The telephone port can only be used if you are a Digital Voice customer but if you are is the Smart Hub acting as an Analogue Telephone Adapter (ATA) and presenting identical analogue functionality to that provided by the Master Socket?

Re: Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

licquorice — Tue, 06 Jan 2026 17:56:05 GMT

Exactly that.

Plenty of information here

Re: Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

POTS — Tue, 06 Jan 2026 18:17:48 GMT

Thanks@licquorice . The relevant bit seems to be

If it really thought necessary to use corded phones in existing extension wiring, this can be achieved if broadband service is via FTTP (Full Fibre to the home) by simply disconnecting the incoming wires from the master socket and connecting the green socket on the hub to any of the phone sockets with a cord consisting of a phone plug at each end.
This is more complicated if broadband service is still delivered via the copper pair as the incoming wires cannot be disconnected and the hub still needs to connect to the master socket. It will require a new extension socket to be fitted adjacent to the master socket and the extension wiring transferred to it. This new socket can then be connected to the green socket on the hub as with FTTP.

It is not phones that are connected to the existing Master Socket though it is a mini PABX. Specifically it is a Panasonic Advanced Hybrid System KX-TES824. Also several cables seem to enter the Master Socket, it is not just a plug entering via the socket.

Do you still think it would be possible to plug this lot into the Hub phone port and get it to work?

Re: Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

licquorice — Tue, 06 Jan 2026 18:25:27 GMT

There should be no reason why it shouldn't work if everything is connected correctly.

Is this a business account rather than residential though?

Re: Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

jac_95 — Tue, 06 Jan 2026 19:20:20 GMT

@POTS

The Panasonic Advanced Hybrid System KX-TES824 seems by default to be configured for 3 analogue PSTN lines??

It may or may not work due to voltage needs, and if it's been setup for multiple lines ect .... If you do get something it may not provide all functionality.

Not sure why you want to use this on a residential phone service but if for a business there dedicated VoIP based solutions that are available from the likes of BT Business

Re: Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

POTS — Tue, 06 Jan 2026 19:49:24 GMT

@licquorice > "Is this a business account rather than residential though?"

It is a residential property with one retired person living there. Unfortunately it is served by two analogue Business Auxiliary Lines which means they are paying 4-5 times more in line rental than I believe they should.

In my layman's view no important functionality would be lost if one of the lines was ceased and the bill halved. It is my belief that the only function that would be lost would be the ability for two external numbers to simultaneously call the property using the same number - which is not required.

It is important that the current number is maintained. You would have thought it would be a simple matter to have BT temporarily disable one line, the homeowner could then do some checks just to make sure everything was working with only one line. If the checks were okay BT could then permanently disconnect the disabled line.

The homeowner could then ask that the single analogue line serving their domestic property was treated as a residential line, which is what it is. That would halve the bill again.

At that point the only agreement the homeowner would have with BT would be for a single residential analogue line. When the changeover to Digital Voice became due the homeowner could request the analogue line be retained and an ATA fitted at the exchange.

In short: bill quartered and digital voice transition completed with no equipment installed in the property, no physical changes made in the property and no visits required by engineers. This is perfect because the homeowner wishes to have no new wiring even if it could be done.

The PABX interfaces with several wired handsets, a voice door entry and door release system and an answerphone.

The problem is that BT Business will not cease one analogue line and leave the other because that is a 'package' change and all new packages have to be digital. Even getting an ATA in the exchange is not straightforward because BT say that will only be done in specific circumstances -that contradicts posts elsewhere on the forum, the default position seems to be to supply a hub to everybody even if they only have a landline contract with BT.

Hence I am checking to see if a hub could be used, but that depends on whether or not the hub can be connected to the PBX without running additional wiring.

What should be simple is a bit of a nightmare.

Re: Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

POTS — Tue, 06 Jan 2026 19:55:53 GMT

Hello@jac_95 our messages crossed. You questions are answered in my recent post.

Re: Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

jac_95 — Tue, 06 Jan 2026 20:08:38 GMT

Hi @POTS

Yes just seen thanks. Ok so this is a BT Business account at present with 2 BT Business lines.

The way BT Business's Digital Voice Phone service works is different to it's residential service in that BT Business tend to supply their customers with BT Business Cloud Voice which can either have a Cisco ATA or VoIP phone supplied. This is different to the residential service where the phone port on the back of the supplied smart hub can be used.

BT Business's products and services and how they deliver them is different from BT Consumer (residential customers) as the business line of business have services aimed at small to medium sized businesses.

Could you not just close the BT Business account and move to BT Consumer??

Otherwise you'll need to discuss options with BT Business on which product and services would suit best - https://business.forums.bt.com/

For information on BT Business's guide to the PSTN closures:

https://business.bt.com/help/article/phone-line-and-services/move-from-traditional-lines-to-the-cloud/the-pstn-and-isdn-switch-off-what-it-means-for-you/

Re: Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

licquorice — Tue, 06 Jan 2026 20:10:23 GMT

Yep, all bets are off. I assumed it was a residential service with a single line serving a PABX. Totally different ballgame.

Re: Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

POTS — Wed, 07 Jan 2026 12:08:10 GMT

@jac_95 wrote > Could you not just close the BT Business account and move to BT Consumer??

Firstly you would have to be absolutely sure that the BT Residential line would work with the existing PABX setup.

New residential lines will not be analogue so it needs to be certain that the existing equipment will work if connected into the telephone socket on the Smart Hub 2. Assuming that would work it needs to be determined if the wiring exists been the two devices. If it does not then it needs to be certain that the BT Digital Voice Adapter can be used to bridge between the PABX and the Hub.

Secondly there is a risk that the existing telephone number could be lost, which is a bit of a no no. Any new residential number can only be assigned the existing number after the Business number is ceased and BT will not guarantee that the number will not be given to a third party before it gets reassigned to the new residential line.

In contrast just cancelling one Business Auxiliary Line and reassigning the other analogue line to be Residential is much simpler and almost just a paper exercise.

Re: Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

POTS — Wed, 07 Jan 2026 12:24:37 GMT

@licquorice wrote> " Yep, all bets are off. I assumed it was a residential service with a single line serving a PABX. Totally different ballgame."

The bet is on whether or not the bureaucratic tangle around using one of the two existing analogue lines can be unraveled. That is a rat's nest almost as bad as the wiring for the system which was originally installed by BT.

There is still the technical problem though which needs to be solved regardless. That is with a single residential line can the PABX and attachments be made to work ?

It is beginning to sound as if possibly the PABX could be plugged into the Smart Hub telephone socket if wiring between the two is available?

If wiring between the two is not possible could the BT Digital Voice Adapter be used as a bridge between the PABX and the hub? I will raise another topic on that question.

Re: Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

licquorice — Wed, 07 Jan 2026 13:05:02 GMT

I am just another customer, I cannot give any guarantees that any specific equipment will work.

However, my opinion is that a single residential line PABX should work when plugged into the green socket in the same way as the analogue phone socket. Not sure how the wiring to the extensions would be achieved, presumably as now. Not entirely sure why a single residential line would need a PABX, but I'm sure you have your reasons.

Re: Is Smart Hub 2 Telephone Port functionally equivalent to the Master Socket phone socket

POTS — Wed, 07 Jan 2026 13:27:48 GMT

@licquoriceI realise that you are a customer - thanks for your input.

The PABX system is old but is actually quite a neat solution for door entry. Phones are on different floors. Any phone can make external telephone calls but they can all be used to speak to somebody who presses the button at the door and to open it if required. You can also make internal calls.

The alternative would be to have a separate door entry and telephone systems. The PABX was actually designed with add in cards for speaking to the door and opening the door - it is not something that has been bolted on.

If they had stopped there then there really would not be a problem. However they put in two lines sharing the same number, which turned the whole thing into a commercial system. I suppose it was originally used for a very early version of home working.